• Journal of the Institute of Electronics Engineers of Korea TC
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• v.45 no.9
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• pp.1-7
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• 2008

The efficient node energy utilization in wireless sensor networks has been studied because sensor nodes operate with limited power based on battery. Since a large number of sensor nodes are densely deployed and collect data by cooperation in wireless sensor network, keeping more sensor nodes alive as possible is important to extend the lifetime of the sensor network. Energy efficiency is an important factor of researches that efficient routing algorithm is needed in wireless sensor network. In this research, I consider some methods to utilize more efficiently the limited power resource of wireless sensor networks. The proposed algorithm is the sink first divides the network into several areas with hop counts and data transmission based on cluster ID. The performance of the proposed algorithm has been examined and evaluated with NS-2 simulator in terms of lifetime, amount of data and overhead.

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1388-1390
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• 1994

A polyimide-based capacitive humidity sensor has been designed and fabricated using silicon integrated-circuit technology, and its performance measured. The sensor showed excellent linearity, low temperature coefficient, and low hysteresis over a wide range of relative humidity and temperature. The signal conditioning circuits for detecting relative humidity and converting it to voltage have been developed based on a charge redistribution between capacitors using switched -capacitors.

• Proceedings of the Korean Information Science Society Conference
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• 2005.07a
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• pp.415-417
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• 2005

Core operations (e.9. TDMA scheduler, synchronized sleep period, data aggregation) of many proposed protocols for different layer of sensor network necessitate clock synchronization. Our Paper mingles the scheme of dynamic clustering and diffusion based asynchronous averaging algorithm for clock synchronization in sensor network. Our proposed algorithm takes the advantage of dynamic clustering and then applies asynchronous averaging algorithm for synchronization to reduce number of rounds and operations required for converging time which in turn save energy significantly than energy required in diffusion based asynchronous averaging algorithm.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.6
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• pp.29-34
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• 2008

In this paper, we propose an entropy-based dynamic routing protocol for supporting effective route stability in mobile ad-hoc wireless sensor networks(MAWSN). The basic ideas and features are as follows. First, construction of entropy-based stable routing route using mobility of nodes between a source node and a destination node. Second, usage of location and direction information for route construction to support resource saving. Third, We consider a realistic approach, in the points of view of the MAWSN, based on mobile sensor nodes as well as fixed sensor nodes in sensor fields while the conventional research for sensor networks focus on mainly fixed sensor nodes. The performance evaluation of the proposed routing protocol is performed via simulation using OPNET. The simulation results show the proposed routing protocol can effectively support route stability and packet delivery ratio.

• Journal of Korea Multimedia Society
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• v.12 no.11
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• pp.1629-1639
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• 2009

This paper describes the environmental monitoring system for supporting comfortable subways based on USN. Our development system includes the sensor field based on integrated sensor, monitoring system for supporting the local and remote monitoring and middle-ware performs the collecting, analyzing, and storing the data. In this paper, we installed the temperature, humidity, micro-dust sensor and water-level sensor for supporting the rail-roads and make up the integrated sensor enables to reuse the analog device from 4~20mA output with connection of wireless sensor device. Middleware includes the modules of collecting, analysis, and storing the data and monitoring system supports the local for administrator and remote monitoring for citizen services based on web. The middleware and monitoring in this paper is comprised of some components can reuse and support the change of application and sensors. Our development system supports the mobility of sensor devices and distributes system. Data collection and management function supported by middleware will use assessment.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.10 no.10
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• pp.1920-1926
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• 2006

With social interest, there hie been a lot of research on the Service Robot but now we are faced with the limitation of single platform. The alternative plan is the Ubiquitous-based Service Robot connected with a Ubiquitous network to overcome this limitation. Systems using RFID(Radio frequency Identification) and supersonic waves appeared for functions such as recognition of surroundings through Ubiquitous Sensor Networks. This was applied to the real robot and we have got good results. However, this has several limitations to applying to low power-based Sensor Network For example, if RFID uses a passive Sensor, the rate of recognition with the distance is limited. In case of supersonic waves, high power is required to drive them. Therefore, we intend to develop RSSI position recognition system on the basis of embodying a Sensor Network Module in this thesis. This RSSI position recognition system only measures RSSI of signals from each sensor nod. then converts them into distances and calculates the position. As a result, we can still use low power-based Sensor Network and overcome the limitation according to distance as planning Ad-Hoc Network.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.9 no.5
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• pp.1289-1295
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• 2008

Recently, it is progressing a study for supporting various application services using OpenAPI(Application Program Interface). But it is not enough a study related OpenAPI(Open Application Interface) to access many collected context data of sensor networks for ubiquitous application services. Therefor, this paper presents Pull/Push service model based on sensor networks, and implements OpenAPI fer Pull/push application services. And, we design and implement OpenAPI using web service for Pull application services. This Pull OpenAPI supports users the context data of temperature and humidity using the remote service based on .Net framework in sensor networks. And, we design and implement OpenAPI using TCP/IP socket interface for Push application services in sensor network. This Push OpenAPI provides users a state of temperature, humidity collecting in sensor networks. Consequently, user can develop easily various application services as supporting OpenAPI instead of closed application interface of sensor networks based on existed specific database.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2007.06a
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• pp.685-689
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• 2007

Recently, wireless communication technology and state of art miniaturization has enabled the wireless sensor network with Smart Environmental sensors. The sensor network is a new field which has been researched vigorously in the ubiquitous computing and Ad-hoc network. How to efficiently use the limited energy in this USN(Ubiquitous sensor Networks) has been debated recently. We utilized the Directed Diffusion and Gossiping concept which is based on the Large scale Glass greenhouse and present a method to prolong the lifespan of the sensor network by operating variable time based this routing information on the average energy leftover. In this paper, we present a method to minimize the energy consumption of sensor node within Glass greenhouses and ensure a stable network operation at the same time through energy efficient routing among sensor nodes.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.8 no.1
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• pp.31-37
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• 2008

In this paper, we propose an entropy-based routing protocol to effectively support both stable route construction and route lifetime in Mobile Ad-hoc Wireless Sensor Networks (MAWSN). The basic idea and feature of the proposed routing protocol are as follows. First, we construct the stable routing routes based on entropy concept using mobility of mobile nodes. Second, we consider a realistic approach, in the points of view of the MAWSN, based on mobile sensor nodes as well as fixed sensor nodes in sensor fields while the conventional research for sensor networks focus on mainly fixed sensor nodes. The performance evaluation of the proposed routing protocol is performed via simulation using OPNET(Optimized Network Engineering Tool) and analysis. The results of the performance evaluation show that the proposed routing protocol can efficiently support both the construction of stable route and route lifetime in mobile ad-hoc wireless networks.

• The KIPS Transactions:PartC
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• v.12C no.6 s.102
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• pp.865-874
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• 2005

The information stored in the computer system needs to be protected from unauthorized access, malicious destruction or alteration and accidental inconsistency. In this paper, we propose an intrusion detection system based on sensor concept for defecting and preventing malicious attacks We use software sensor objects which consist of sensor file for each important directory and sensor data for each secret file. Every sensor object is a sort of trap against the attack and it's touch tan be considered as an intrusion. The proposed system is a new challenge of setting up traps against most interception threats that try to copy or read illicitly programs or data. We have implemented the proposed system on the Linux operating system using loadable kernel module technique. The proposed system combines host~based detection approach and network-based one to achieve reasonably complete coverage, which makes it possible to detect unknown interception threats.